In your own words, describe two conditions that are necessary for an eclipse to occur

1. the Moon must be in line with the Earth and Sun - New Moon for a solar eclipse and Full Moon for a lunar eclipse.2. the Moon must be at one of its nodes. Most of the time the Moon at New or Full passes above or below the Sun because its orbit is tilted relative to the ecliptic. An eclipse can occur only when it is at a node, in other words crossing the ecliptic.

The independent variable is the type of music.the dependent variable is the pulse rate.the intervening variable is the age of the subject.if the mother does not like rock, her pulse is likely to not increase.the same might be true for the sister.the friend may like rap and gets excited.to establish cause/effect relationship, all of the subjects must be consistent.hope i .